Underreamer



March 10, 1931.

s.. HIGHFILL ET AL UNDERREAMER Filed Jan. 11, 192'? 2 Sheets-Sheet 1 5. ATTORNEY Mil Patented Mar. 10, 1931 UNITED STATES PATENT QFFEE SAMUEL L. HIGHFILL, or wmmw, KANSAS, AND ROBERT P. MAYs, or CLEVELAND,

' OKLAHOMA r UNDERREAMER Application filed J'anualy 11, 1927. Serial No. 160,427.

Our invention relates to well drilling tools and more particularly to improvements in under-reamers.

It is an object of the invention to provide being provided with a plurality of slots to receive the lugs, whereby the cutters may be turned in the socket to change the position of their seat; p

A further obj ect of the invention is to provide a tool of'the above-mentioned character 4 following description.

In the accompanymg drawings, forming a part of this specification and in which like numerals are employed to designate like 7 parts throughout the same,

' Fig. 1 is a front elevation of our improved under-reamer,

Fig. 2 is a longitudinal sectional view of the same,

Fig. 3 is an enlarged fragmentary sectional view of the trip mechanism, Fig.4 is a cross section takenon lines 4.4

'of Fig. 2, Fig. of Fig. 2, H V

Fig. 6 is a cross section taken on line 6-6 of Fig. 2, and

Fig. 7 is a cross section taken on lines 7- 7. I 'of Fig.2. 1

5 is 'a cross section taken on lines 5-5- In the drawings, wherein for the purpose of illustration we have shown a preferred embodiment of our invention, the numeral 5, designates the reamer body which has an annular socket 6 in its lower end to receive the shanks 7, of the cutters 8, as more clearly shown in Fig. 2. The cutters are substantially semi-circular in cross section and each is formed with a shoulder 9, on its outer face, approximately midway its length which squarely abuts against the end of thesocket when the cutters are in operative position. The shanks 7, of the cutters are provided adjacent their upper ends and centrally thereof, with outwardly projecting lugs 10, adapted to loosely fit in slots 11 extending through the wall of the socket. The socket is provided with four of the slots 11, arranged around the wall at equal distances, permitting the cutters to be turned a quarter of a turn when their seats become Worn. When,

the cutters are in operative position the inner face of the shanks at the upper end are disposed on a plane parallel with the longi tudinal axis of the body, as at 12, and from the point 13, gradually incline downwardly at an angle to the longitudinal axis of the body, as at 12', the outer face of the cutters below the shoulder 9, being beveled at a corresponding angle, so the body of the cutters will be of uniform thickness. Thus, it is seen that the cutters are capable of collapsing, so as to lie within the circumference of the reamer body and a wedge-shaped block 14, connected to the lower end of the mandrel 15 is adapted to spread or expand the cutters to cutting position, The mandrel 15, extends upwardly through the axially disposed bore 16 of the reamer body having an expansion spring 17 mounted thereon, one end of which is seated on the shoulder 18, at the lower end of the bore and its other end bears against the end of the sleeve 19, threaded on the upper end of the mandrel, as at 19. The spring 17, normally exerts an upward thrust upon the mandrel causing the wedge block 14: to automatically. expand and firmly hold the cutters inoperative position. The inner face of the cutters is provided with a central longitudinal groove 20, to receive the mandrel which prevents withdrawal of the cutters until the mandrel is removed; lVhen the wedge block is withdrawn, the mandrel serves as a fulcrum for the upper end of the cutters, whereby the lower ends will automatically collapse.

The trip mechanism for holding the wedge block in an inoperative position, while the reamer is being inserted or removed from the well, as more clearly shown in Fig. 3,.

a cross bar 24:, extending through slots 25 in the grooves 22, the trips being sildable on the ends of the bar and provided with transverse pins 26 extending through slots 27 in the ends thereof. The cross bar extends through an opening 27 in the sleeve 19 and is normall seated on the u per end of the Y pl mandrel between the prongs 2S, projecting upwardly therefrom. The cross bar is held against transverse movement by the locking pin 29, threadedly mounted in the sleeve 19, as at 30, having its lower end bearing against the upper edge of the cross bar. Thus, it is seen that the cross bar 2%, locks the sleeve and mandrel 15 against rotary movement, maintaining the wedge block 1 in proper alinement with respect to the inner faces of the cutters, insuring free longitudinalmovement of the mandrel.

The upper end or" the body 5 is interiorly threaded and tapered, as at 31, to receive the tapered threaded nipple 32 of the cap 33, the upper end 01. the cap being tapered and threaded, as at 3%,for connecting the tool with the usual string of tools. The cap 33 has its lower end recessed, as at 35, to receive the upper ends of the sleeve 19 and pin 29. The bottom of the block 14;, has a screw-threaded recess 36, adapted to receive an eye bolt, not

shown, to permit manual extraction of the block.

In operation, when it is desired to insert the tool in a. well, the wedge block is extracted, through the medium of an eye bolt, drawing the trips 21 downwardly into the lower por-.

tion of the grooves 22 and compressing the coil spring 17. The trips are retained in the lower portion of the grooves by a clamping ring or other suitable device, well known in the art, until the reainer is inserted in the well casing, whereupon the casing will retain the trips in place. the lower end of the casing the trips-are released and the upward thrust of the coil spring forces the mandrel upwardly, causing the'Wedge' block to expand the cutters and When the reamer passes solidly hold them in an operative position. The tension of the spring 17 is adjusted by the sleeve 19, threaded on the upper end of the mandrel and when the tool is assembled the cross bar o24t, locks the mandrel and sleeve against rotary movement, 'maintaining the wedge block in proper alinement to insure expansion or" the cutters. WVhen the tool is removed from the well, the lower edge of the casing engages the trips, forcing the mandrel downwardly and releasing the wedge block, thus permitting the cutters to collapse.

It is to be understood that the form of our invention is to be taken as a preferred example or" the same and that certain changes in the shape, size and arrangement of the parts, may be made without departing from the spirit of the invention or the scope of the subjoined claims.

Having thus described our invention, we

claim: 7

1. In an under-reamer, the combination of a body, cutters mounted in said body, a mandrel disposed axially of said body having means for expanding said cutters, a spring."

mounted on said mandrel, a sleeve threaded on the upper end of said mandrel for adjusting the tension of said spring, said sleeve having opposed transverse slots, a cross bar slidably mounted in said body and extending through the slots in said sleeve, and trips connected with said cross bar for controllingthe longitudinal movement of said mandrel.

2. In an under-reamer, the combination of a body, cutters mounted in said body, a mandrel disposed axially of 7 said body having meansfor expanding said cutters, a spring mounted on said mandrel, asleeve threaded on the upper end of said mandrel for adjusting the tension of said spring and a cross bar extending transversely through said sleeve and having connection with said .mandrel,the ends of said cross bar being slidably'mounted in slots through the walls of said body.

3. In an under-reamer, the combination of a body, cutters mounted in said body, a mandrel disposed axially o'f'said body having means for expanding said cutters, a spring mounted on said mandrel, a sleeve threaded on the upper end of said mandrel for adjust ing the tension of said spring, across bar slidably mounted in said body extending transversely through said sleeve and having connection withsaid mandrel and a pin threaded in said sleeve having engagementwith'said cross bar to hold the same" against lateral movement.

4. In an under-reamer, thecombination of a body, cutters mounted in said body, a' mandrel disposed axially of said'body havingmeans for expanding said cutters, spaced prongs protruding from the'upper end of said mandrel, av spring mounted on said mandrel, a sleeve threaded on the upper end ofisaid mandrel for adjusting the tension-of said spring and a cross bar extending transversely through said body and sleeve adapted to seat on the upper end of the mandrel between said prongs.

In testimony whereof we aifix our signatures.

SAMUEL L. HIGHFILL. ROBERT P. MAYS. 

